How to add more battery power?

[Stan&Jacquie]

Here's a brain teaser for you? I presently run 4 golf cart batteries on my battery tray providing about 440 amp hrs of storage. I would like to increase that number but whatever I do must fit on my current battery tray. What type/size/# of batteries will give me more power storage and still fit on my current battery tray? My coach is a 2007 Monaco Knight DFT diesel.


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[twinboat]

If you have some extra height they make tall GP16 batteries that have the same footprint of GC2s.

Trojan battery also makes higher capacity GC2 batteries. Up to 245 AH, I believe.

[K7JV]

Unless you add a second location, or unless you have a lot of extra room in your existing tray, you aren't going to get a significant increase in ampere-hours of capacity. Like "Twinboat" said, if you can add height, you can gain some. If you do add a second location, try to keep them as close to one another as you can, and absolutely make sure they are ALL the same brand, type, size, rating and age. Do look at the AH ratings of lead-acid, GEL and AGM and see which will give you the greatest AH capability within your size restraints. The concept of "best" is in the eyes of the beholder. Each have their advantages and disadvantages.

[K7JV]

Also, make sure you understand what the AH ratings mean in your installation. Let's assume you have two batteries, and they are rated 100 AH. If they are six volt batteries in series, your bank will be rated at 100 AH, even though there are two. Each battery is delivering 100 AH at a nominal terminal voltage of 6 volts, for a total of 100 AH at 12 volts. If they are 12 volt batteries in parallel, each rated at 100 AH, you will have 200 AH available, as they will be delivering energy side-by-side, or in parallel, rather than in series. Those AH numbers are hypothetical, but hopefully it shows the difference in how 6V and 12V battery banks will perform with respect to their individual battery ampere-hour ratings.

[twinboat]

Originally Posted by K7JV

Also, make sure you understand what the AH ratings mean in your installation. Let's assume you have two batteries, and they are rated 100 AH. If they are six volt batteries in series, your bank will be rated at 100 AH, even though there are two. Each battery is delivering 100 AH at a nominal terminal voltage of 6 volts, for a total of 100 AH at 12 volts. If they are 12 volt batteries in parallel, each rated at 100 AH, you will have 200 AH available, as they will be delivering energy side-by-side, or in parallel, rather than in series. Those AH numbers are hypothetical, but hopefully it shows the difference in how 6V and 12V battery banks will perform with respect to their individual battery ampere-hour ratings.

A good explanation but most 6 volt batteries will have double the AH capacity of a "same size" 12 volt battery so things even out.

[Captjake1]

Made a rack in the engine bay to move my chassis batteries to. That freed up a whole tray to double my coach batteries. Stole the idea from kketterling.

[Mr_D]

Lithium batteries but $$$

[Frutza]

How high is your compartment ? Can you make a shelf over the top?

[twinboat]

Originally Posted by K7JV

Unless you add a second location, or unless you have a lot of extra room in your existing tray, you aren't going to get a significant increase in ampere-hours of capacity. Like "Twinboat" said, if you can add height, you can gain some. If you do add a second location, try to keep them as close to one another as you can, and absolutely make sure they are ALL the same brand, type, size, rating and age. Do look at the AH ratings of lead-acid, GEL and AGM and see which will give you the greatest AH capability within your size restraints. The concept of "best" is in the eyes of the beholder. Each have their advantages and disadvantages.

Actually you can double your 400 AH with 4 Trojan L16 batteries. They are 435 AH each. Just real tall and heavy.

[wa8yxm]

Well you can get a FEW more amp hours but not many. I replaced my original 220 amp hour batteries with 230 when they needed it.. That gives you an idea of how much more.

Alas, a significant incrase is not possible without expanding the battery tray.. Which is what I would recommend.. a 2nd battery tray and more pair.

[kketterling]

Beat me to the same response. Key is where the existing engine batteries are located now. If next to house batteries then it's relatively easy to increase house bank by relocating engine batteries.

[vito.a]

Another way to approach this issue is to reduce your requirement. My new Energy Star residential fridge only uses .8 amps at 110v; and that is only when the motor runs. This translates to about 8 amps at 12v from the inverter. This cut my requirement greatly.

[vsheetz]

Originally Posted by vito.a

Another way to approach this issue is to reduce your requirement. My new Energy Star residential fridge only uses .8 amps at 110v; and that is only when the motor runs. This translates to about 8 amps at 12v from the inverter. This cut my requirement greatly.

Agreed. Conservation is more easily done and usually less expensive. LED lighting, low power TV/SAT/music systems, etc. If already done or still not good enough, add batteries and

[bluepill]

Another option is to use some AGM batteries as a different bank. You can put them inside the coach. Maybe under the bed? Or a basement compartment?

Downside is that they would require a dedicated charger due to different chemistry, and you would have to devise a switchover strategy to switch between banks.

Another strategy would be to have the different banks feed different circuits. Example: Use your existing bank to power a large inverter (which I assume you already have). New, smaller bank for small DC loads like lighting, furnace blower, maybe another inverter for small 120 volt loads.